3-Chloromethylpyridine hydrochloride, of chemical formula: ##STR1## is used in the preparation of various pharmaceuticals. There is accordingly a requirement that it be produced in a highly pure form.
U.S. Pat. No. 5,686,619 Bay et al. and its parent patent U.S. Pat. No. 5,521,316 describe a process for preparing chloroalkyl pyridinium hydrochloride compounds with high purity levels and in a free-flowing, non-dusting form. In the process described in those patents, an initial, preliminary step of preparation of hydroxy alkyl pyridinium hydrochloride compound is required, involving reaction of hydroxy alkyl pyridine compound with hydrogen chloride. Then a solution or dispersion of the corresponding hydroxy alkyl pyridinium hydrochloride compound so prepared, in a medium comprising a non-solvent for the chloroalkyl pyridinium hydrochloride, is reacted with a large excess of thionyl chloride to form the chloroalkyl pyridinium hydrochloride as a solid in the reaction mixture.
It is an object of the present invention to provide a new and improved process for preparing chloromethylpyridine hydrochlorides.